Mishnah 2 and 3
A person functions at three levels. The highest level is tzelem, a reference to mankind’s image of G-d, an aspect of which is the independent spirit of individual existence. The middle level is tzurah, which literally means form. It is the aspect of personality that seeks to impose form and structure on things, on oneself and on others. The level called chomer, is the physical, pragmatic plane of existence. The qualities of tzelem and tzurah are, of course, more spiritual and intellectual whereas chomer is totally physical.